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See Section 254
No Sound  Switches or rheostats on amplifier rack set incorrectly.Set switches and rheostats correctly.
Sound can be obtained from one amplifier rack and not from another. Defective amplifier rack equipment. Operate using the good amplifier rack. Check all tubes, meter readings, and fused of the defective rack as soon as convenient. See section 176.
Motor-generator sets associated with both amplifier racks fail to start. Open in power line circuit to motors of M-G sets. Check all line switches in the power circuit. Replace fuses if blown.
Fuses in the low voltage generator circuit blow as indicated by the amplifier tubes and exciter lamps failing to light. Short circuit in the "A" supply circuit. Change over to other amplifier rack. If fuses blow on this rack alsit the indication is that the short is in the exciter lamp circuit of the projector. See section 246.
Tube in voltage amplifier fails to light. Tube burned out. Change to other amplifier rack and change tube when convenient.
Low Volume   Defective tube in the voltage amplifier. Change to the other amplifier rack and replace all the voltage amplifier tubes when convenient.
Noise or "Motor-Boating" Noise obtained when using either amplifier rack. Loose ground connections on the projector. Clean and tighten the projector ground connections.
Noise obtained from one amplifier rack only.Loose connection on the amplifier rack. Operate using the other amplifier rack. Inspect all connections and tighten where necessary.
Defective "C" batteries. Operate using the other amplifier rack. Replace "C" batteries as soon as convenient.
Hum Hum heard from both stage and monitor speakers. Dirty commutator on M-G set. Change to other amplifier rack. Clean commutators. See section 36.
Loud hum heard only from monitor speaker. Defective UX-280 tube (or Rectox unit) on monitor speaker. Replace UX-280 on monitor speaker. Where Rectox unit is used, turn of the AC power to the monitor and notify the RCA service engineer.
Whistling Sound. Readings on plate current meters of power amplifier not balanced. Unbalanced plate currents of power amplifier tubes. Balance plate current readings. If this does not correct the trouble change to other amplifier rack. Replace the power amplifier tubes when convenient.


Chapter Fourteen Pages
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